SU833491A1 - Extractional-photometric method of antimony determination in bronzes - Google Patents

Description

(54) EXTRACTION-PHOTOMETRIC METHOD FOR DETERMINING ANTIMONY IN BRONZES

one

The invention relates to analytical chemistry and is intended for the extraction-photometric determination of microgram amounts of antimony in bronze.

. The known method of extraction-photometric determination of antimony, based on the dissolution of bronze in a mixture of concentrated HC1: HNO3 (3: 1), precipitation of antimony with solutions of ferric chloride and ammonia, dissolving the precipitate in HCL (1: 1) by reducing antimony with a solution of tin chloride (II ), the oxidation of antimony with sodium nitrite to SbClg, the formation of an ionic associate of antimony (V) with methyl violet, the extraction of the ionic associate with toluene and photometric measurement at 610 nm 1.

In the known method, many operations are required to achieve the goal, the course of analysis is rather long, the method is laborious. In addition, the method does not have sufficient accuracy.

The closest to the proposed invention is a method of extraction-photometric determination of antimony in bronze, based on the conversion of antimony to the ionic association with brilliant green.

The method is as follows.

A portion of bronze is dissolved in 8 ml of a mixture of acids Hg5O,: NMO3 (3: 1) in a glass with a capacity of 250 ml, covered with a watch glass, while heating. After the sample is dissolved, the watch glass is rinsed with water and evaporated until the measured acid vapor appears. After cooling the solution, wash the walls of the glass with a small amount of water and repeat the evaporation. To the residue, 20 ml of hydrochloric acid diluted 3: 1 are carefully added, the salts are dissolved and transferred into a 100 ml volumetric flask, then topped to the mark with hydrochloric acid diluted 3: 1 and stirred.

In a separating funnel with a capacity of 100-150 ml, take 5 ml of the resulting solution, add two drops of vegetable. tin chloride thief, stirred and left for 1 min. Then, 1 ml of sodium nitrite solution is injected, well

Claims (2)

mix and leave for 5 minutes. Thereafter, 1 ml of a saturated urea solution is added, stirred for 30 seconds and i diluted with water to 50 ml. Then 1 ml of brilliant green solution, 30 ml of toluene are introduced and extracted for 1 minute. After the phase separation, the lower aqueous layer is discarded, and the organic layer is poured into a dry glass with a capacity of 50 ml containing 0.3-0.5 g of anhydrous sodium sulfate. After 10 min, the optical density was measured on a spectrophotometer (wavelength 640 nm) or on a photoelectric colorimeter with a No. 8 light filter (wavelength 597 nm) in a cell with a layer thickness of 1 cm. The comparison solution is toluene. The content of c / gm is found on the calibration curve 2. The disadvantages of the method are the need to preliminarily isolate, reduce and oxidize antimony to SbCU, the accuracy of the analysis is insufficient. The purpose of the invention is to increase accuracy, reduce labor intensity, accelerate analytical determination by preventing the hydrolysis of SbCl. This goal is achieved by using as a solvent a mixture of concentrated HCl and (3: 1) to oxidize antimony to SbC, remove excess HNOj, adding concentrated HCl to retain antimony in the form of SbClI, and using azine dye — Rhoduline Violet as an organic reagent for antimony to antimony — which the extraction of the photometric determination of antimony does not interfere with other components of bronze. The proposed method is as follows. A portion of the analyzed bronze is dissolved and antimony is oxidized to SbCl7 when heated in a mixture of concentrated HC1 and HMO3 (3: 1), an ionic antimony associate is formed with an azine dye, Rhodulin Violet, the formula of which is Cgi H, Mch (C1), then extracted with a mixture of benzene and methyl ethyl ketone (4: 1), the organic phase is centrifuged and photometric at 552 nm. Solutions were prepared from o.ch., x.h. in double distilled water. The initial concentrations of the solutions are as follows: 4.1-10 M Roduline Violet and 8.210 M SbCi; Antimony solutions, solution A was prepared as follows. 0.05 g of antimony brand Suoo dissolved when heated in 10 ml of a mixture of concentrated no and NYOZ (3: 1). Excess HNOi is removed by triple evaporation from concentrated t / t1-4 of HCI. The solution is transferred to a 500 ml volumetric flask and diluted to the mark with concentrated HCl. The solution prepared in this way contains antimony in the reactive form. 1 ml of the solution contains 0.0001 g of antimony. Solution B is prepared as follows. 10 ml of solution A is poured into a 10 ml volumetric flask and diluted to the mark with concentrated HCl. 1 ml of solution B contains 0.00001 g of antimony. Example. A portion of bronze (0.2-2.0 g) is dissolved by heating a mixture of concentrated HCI and HN03 (3: 1) in a 250 ml beaker covered with a watch glass. Excess HM03 is removed by threefold evaporation from concentrated HCl. The glass is cooled, the walls of the glass and the watch glass are washed with concentrated HC. The solution is transferred to a volumetric flask with a capacity of .50 ml and diluted with concentrated HCl to the mark. Depending on the antimony content, from 1.0 to 2.5 ml of the obtained solution are placed in a 25 ml volumetric flask, concentrated NP is added to a total volume of 2.5 ml, about 24 ml of water are added, 1 ml of Rhoduline Violet ( 4)) and diluted to the mark with water. Stir and extract 20 s with 25 ml of a mixture of benzene and methyl ethyl ketone (4: 1). The organic phase, separated from the aqueous phase, is centrifuged and photometrized at L 552 nm, with a layer thickness of 50 mm. The amount of antimony is determined from the calibration graph. To obtain a calibration graph, a 25 ml volumetric flask is placed from 0 to 2.5 ml of the standard solution of antimony B, concentrated HCI is added to a total volume of 2.5 ml and then proceed as in the analysis of bronzes. The method of extraction-photometric method for the determination of microquantities of antimony using roduline violet was tested by analyzing standard bronze samples of the following numbers and grades: br 10.2, M 254x; BrAZh 9-4, M76x-, BrA5, BrA7, M95x, b ROC 4-3, M 246x; BrAMts, M 88x. The use of the azulin dye rhoodulin violet makes it possible to determine 0.001 / o antimony in bronze without first isolating antimony. This is possible due to the high selectivity of the method, namely, the definition of antimony does not interfere with copper, when the ratio C: Sb is 80000: 1, click on - As: Sb 46000: 1, tin - Sn: Sb 12500: 1, iron - Fe: Sb 900 : 1, lead - Pb: Sb 11000: 1, nickel - Ni: Sb 14000: 1, zinc Zn: Sb 180000: 1, bismuth - & i: Sb 92000: 1, manganese - Mp: Sb 92000: 1, aluminum - Al: Sb m 5000: 1, magnesium - Mg:: Sb 192000: 1, cobalt - Co: Sb 32000 lpttT -CUA. 1 tellurium, - Those: Sb 46000: 1, selenium - Se: Sb- 92000: 1, chromium - Cr: Sb 40000: 1, calcium - Sa: Sb 18000: 1, cerium - Ce: Sb 18000: 1, germanium - Ge: Sb 23000: l, indium - In: Sb 16000: 1, gallium - Ga: Sb 9000: 1, cadmium Cd: Sb 6000: 1. The table shows certain and certification amounts of antimony in bronze. As can be seen, the data obtained by the proposed method are in good agreement with the certification data. In addition, the extraction-photometric method using azin dye rhodulinovogo BROTs 10-2, M 254 x0.0011 + 0.00020,00094 BrAZh 9-4, M 76 X0,, 00020,002240 BrA5, BrA7, M 95x0, 00020 , 00340 BrOC 4-3, M 246x0.0052tO, 00040.00516 BrAMts, M 88x0,, 0070.0460 violet is distinguished by its speed, good reproducibility and accuracy. These advantages make it possible to use the proposed method in other laboratories for the determination of trace amounts of antimony in bronze. An Extradition Photometric Method for Determining Antimony in Bronze, including dissolving a sample in an acid mixture, converting antimony in the form of SbClJ to an ionic associate with an organic dye, extracting and photometry, in order to improve the accuracy and speed up the analysis by preventing hydrolysis SbClJ, the dissolution and oxidation of antimony is carried out with a mixture of concentrated hydrochloric and nitric acids (3: 1) and after removing excess nitric acid, concentrated hydrochloric acid is added, and in ETS dye used rodulinrvy violet. Sources of information taken into account in the examination of 1. Zavodsk Lab, 1953, v. 19, no. 7, 771-772. 2. GOST, 1953, 10.7 4 (prototype).